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edweir
Joined: 07 Jan 2010
Posts: 4
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| A numeric expression must appear here: error |
 Posted: Wed Jan 20, 2010 11:31 pm |
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CCS PCM C Compiler, Version 4.057
PIC16F886
| Code: |
int16 t1; //is defined up at the top of the main loop
//this is from the main loop
if (data_flag) {
printf("data_flag triggered\n\r");
if (data_collected <= max_data) {
if (packet_index < sizeof(packet0)) {
for(k = 0; k <= (active_channels-1); k++) {
set_mux_chan(k);
t1 = get_adc_data();
packet0[packet_index + 2*k] = make8(t1,1); //MSByte of data
packet0[packet_index + 1 + 2*k] = make8(t1,0); //LSByte of data
data_collected = data_collected + 2*active_channels;
}
packet_index = packet_index + active_channels*2; // the 2 multiplier is due to 16 bit or 2 bytes of data
}
if (packet_index + active_channels*2 > sizeof(packet0)) {
ptr = packet_num*packet_index;
writep_ext_eeprom(ptr, packet0, sizeof(packet0));
packet_num++;
packet_index = 0;
}
}
else end_flag = 1;
}
//bit banging to an external ADC
int16 get_adc_data() {
int16 temp_val, tmp1;
int c;
printf("Getting Data\n\r");
temp_val = 0b0000000000000000;
output_high(MUX_EN); // set MUX enable bit to push through mux channel
// set conversion bit low to start data collection
output_low(ADC_CONV);
// cycle through four clock cycles to get rid of the first 4 zeros
for (c = 0; c <= 3; c++) {
output_high(ADC_SCK);
output_low(ADC_SCK);
}
//### look at breaking this out... speed up the process significantly
// go through 16 bits of data
for(c = 0; c <= 15; c++){
output_high(ADC_SCK);
if (input(ADC_DIN)) tmp1 = 0b0000000000000001; // \
else tmp1 = 0b0000000000000000; // /
temp_val = (temp_val|(tmp1<<(15-c))); // instruction time decreases with more shifts
//nine clock cycles before here
output_low(ADC_SCK);
}
output_high(ADC_CONV); // shut down convert bit, 20 bits should have been read: 4 zeroes and 16 bits of data.
output_low(MUX_EN); // disable MUX enable
printf("data = %lu\n\r", temp_val);
return temp_val;
} // end get adc data
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Calling the above function in the main loop with t1 = get_adc_data(); causes the " A numeric expression must appear here ". I was able to call this function before I implemented the return, so I'm sure that's the problem but I don't know how to fix it.
Thanks for the help.
Erik
_________________
Cor. 's a rough world 'innit? |
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Wayne_
Joined: 10 Oct 2007
Posts: 681
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| Posted: Thu Jan 21, 2010 3:33 am |
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Which line is it complaining about ?
Where is the code that calls get_adc_data ?
Is the function defined after main or before ?
Where is the prototype ?
I suspect you modified the function header to add a return value but did not change the function prototype! |
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Guest
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| Posted: Thu Jan 21, 2010 7:57 am |
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You're absolutely correct. I had, in fact, changed the header to include the returned int16... but at the same time I removed a passed variable to the function which I didn't change the function prototype to reflect! Classic too-tired too-late...
Thanks! |
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